Sample 1.4 GHz of the rotational spectrum of glycinamide at 50°C illustrating the absence of characteristic spectral patterns. Overbars in the experimental spectrum (top panel) mark J = 34 ← 33 transitions between rotational levels with K_a = 0 and 1,with each marked line corresponding to an overlap of a pair of stronger μ_a-dipole, and a pair of weaker μ_b-dipole transitions. The frequency span of the bar indicates the significant magnitude of the splitting between two substates for each of the three tunnelling doublets. Blue markers indicate ground-state transitions in the data set used for determining spectroscopic constants, while the bottom panel displays collected predictions made on the basis of the final fits.